Fuel injection system



United States Patent C FUEL INJECTION SYSTEM George M. Holley, Sr., Grosse Pointe Farms, Mich., as-

signor to Holley Carburetor Company, Van Dyke, Mich., a corporation of Michigan Application December 9, 1955, Serial No. 552,146 15 Claims. (Cl. 123-119) The present invention relates to a fuel injection system.

It is an object of the present invention to provide a fuel injection system including an induction tube, means for supplying a rich fuel-air mixture to the induction tube, means responsive to engine speed for controlling the quantity of mixture, and means responsive to manifold vacuum for controlling the richness of the mixture.

More specifically, it is an object of the present invention to provide in an internal combustion engine, a fuel injection system comprising an induction tube having a throttle therein, a passage for supplying a rich fuel-air mixture to the tube, a valve in said passage, and mechanical means connecting said throttle and valve for simultaneous operation.

It is a further object of the present invention to provide a system as described in the preceding paragraph including an engine driven fuel-air pump, preferably of the positive displacement type, to supply air to said passage at a rate dependent upon engine needs, and a metering valve responsive to vacuum within said tube downstream from said throttle for controlling the supply of fuel to the air supplied by said pump to said passage.

Other objects and features of the invention will become apparent as the description proceeds, especially when taken in conjunction with the accompanying drawings, wherein:

Figure 1 is a diagrammatic view illustrating the association of operating elements.

Figure 2 is a fragmentary section on the line 22, Figure 1.

The present invention is intended for fuel and air injection to an internal combustion engine and the illustrated system is well adapted to supply the required fuelair mixture to each cylinder thereof.

Referring now to the drawing, there is illustrated an induction tube herein illustrated as provided with a restricted portion defining a venturi 12. Located closely adjacent the throat of the venturi 12 is an inlet'nozzle 14 for supplying a rich fuel-air mixture under pressure to the induction tube 10. The rich fuel-air mixture is supplied-to the nozzle 14 througha mixture passage 16. Located in the induction tube 10 is a throttle 18 and a mixture valve 20 is provided controlling flow of the rich fuel-air mixture through the passage 16 and nozzle 14 to the interior of the tube 10. The throttle 18 is under manual control of the operator as by a foot pedal or the like, and the throttle 18 and valve 20 are mechanically interconnected. The arrangement is diagrammatically illustrated in Figure 2 as comprising a rotary valve element 21 having a passage 22 extending therethrough mechanically connected as by a shaft 23 to rotate simultaneously with the throttle 18. The arrangement is such that the fiow of the rich fuel-air mixture to the tube 10 'is controlled conjointly with the flow of air admixed .A fuel-air pump indicated generally at 24 is provided comprising a cylinder 26 and a piston 28 therein. The

7 2,863,434 Patented Dec. 9, 1958 piston 28 is reciprocated by a rotary part connected to the engine, such part herein being illustrated as an eccentric 30 operating in a circular sleeve portion 32 of a connecting rod 34 pivotally connected to the piston 28 as indicated at 36. Air is supplied to the cylinder 26 through a passage 38, the admission of air being past a light check valve 40 operable to prevent return of air. The outlet of the pump is through a port 42 closed by a check valve 44 normally held in closed position by a relatively light compression spring 46.

The passage 38 is provided with a restricted portion defining a venturi 50 in which the passage of air produces a pressure below atmospheric. A fuel tank or float chamber is indicated diagrammatically at 52 through which fuel may be drawn into the venturi. 50 through a passage 54 controlled by a needle valve 56. The needle valve is illustrated as connected to a piston 58 movable in a cylinder 60 and urged upwardly therein by a light tension spring 62, the other end of which is secured to a support 64 which preferably is vertically adjustable to control the tension of the spring 62. The cylinder 60 below the piston 58 connects by a passage 66 tothe interior of the induction tube downstream of the throttle 18.

From the foregoing it will be apparent that the operation of the pump 24 is dependent on engine speed, and the quantity of fuel admitted past the needle valve 56 is in general dependent on engine load. The throttle 18 together with the mixture valve 20 are under the control of the operator. Under these conditions, in general the quantity of fuel-air mixture delivered through the tube 10 is dependent on engine speed as modified by the position of the throttle. Moreover, as the throttle is moved to modify the flow of air therethrough, a corresponding movement of the mixture .valve 20 takes place tending to keep the richness of the mixture supplied through the tube 10 approximately the same.

Since the flow of the rich fuel-air mixture through the passage 16 is dependent primarily upon mixture valve 20, the operation of the pump 24 may be considered as basically controlling the pressure of the rich fuel-air mixture supplied to the mixture valve 20.

With the throttle 18 and mixture valve 20 in an intermediate position, an increase in load on the engine results first in a decrease in engine speed and a decrease in the vacuum applied to the underside of the piston 58. This permits the spring 62 to move the piston upwardly, thus opening the metering valve 56 and admitting more fuel to the air supplied to the pump 24. At the same time, the slower operation of the engine results in less air being supplied by the pump and a corresponding decrease in the pressure of the rich fuel-air mixture and of the quantity of such mixture passing from the nozzle 14 into the tube 10. The slower engine speed also results in less atmospheric air being drawn through the induction tube 10.

In general, under an increase in load and Without adjustment of the throttle 18 or mixture valve 20, the system tends to deliver a lesser quantity of a richer mixture to the induction tube while at the same time a lesser quan-' of the throttle valve correspondingly opens the mixture valve 20 and tends to immediately reduce the vacuum existing downstream from the throttle 18. This reduction in vacuum in turn results in opening movement of the metering valve 56 so that more fuel is supplied to the air being drawn to the pump 24. Thus, initially, a richer mixture is supplied to the rich fuel-air mixture passage 16. At the same time, opening movement of the throttle and mixture valve provides for both an increased quantity of the rich fuel-air mixture being supplied to the induction tube and more air flowing through the induction tube to the cylinder of the motor. Conversely, assuming a steady condition, as the throttle is moved toward closed position, the increased vacuum effective on the passage 66 immediately tends to move the metering valve 56 toward closed position, thus supplying a leaner mixture of fueland air to the pump 24. Closure of the throttle 18 reduces the quantity of air and air-fuel mixture flowing through the tube 10, and as the engine slows, increasing pressure below the piston 58 opens the metering valve 56. At the same time, the speed of operation of the pump 24 diminishes, thus decreasing the pressure of the rich fuel-air mixture supplied to the nozzle 14.

By properly proportioning the parts of the system, it may be made to produce injection of a rich fuel-air mixture, the quantity and richness of such mixture being as required for the most efficient engine operation under all conditions.

The drawings and the foregoing specification constitute a description of the improved fuel injection system in such full, clear, concise and exact terms as to enable any person skilled in the art to practice the invention, the scope of which is indicated by the appended claims.

What I claim as my invention is:

1. A fuel injection system for an internal combustion engine having a manifold comprising an induction tube having a throttle therein, a nozzle for injecting a rich fuel-air mixture into said tube, a fuel-air pump, a passage of which said pump forms a part extending to said nozzle, a carbureting unit including a fuel metering valve connected to said passage for supplying fuel to air passing therethrough, a mixture valve in said passage between said nozzle and said pump and unit, means connecting said throttle and mixture valve, and means responsive to load on the engine controlling said metering valve.

2. A fuel injection system for an internal combustion engine having a manifold comprising an induction tube having a throttle therein, a nozzle for injecting a rich fuelair mixture into said tube, a fuel-air pump, a passage of which said pump forms a part extending to said nozzle, a carbureting unit including a fuel metering valve connected to said passage for supplying fuel to air passing therethrough, a mixture valve in said passage between said nozzle and said pump and unit, means connecting said throttle and mixture valve, and means responsive to manifold vacuum controlling said metering valve.

3. A main fuel injection system for an internal combustion engine having a manifold, comprising an induction tube, a throttle in said tube, a passage including a fuel-air pump for supplying a rich fuel-air mixture under pressure to said tube, a valve in said passage, and mechanical connections requiring simultaneous movement of said valve and throttle.

4. A main fuel injection system for an internal combustion engine having a manifold, comprising an induction tube, a throttle in said tube, a passage including a fuel-air pump for supplying a rich fuel-air mixture under pressure to said tube, a valve in said passage, mechanical connections requiring simultaneous movement of said valve and throttle, and means responsive to manifold vacuum for controlling the richness of the mixture in said passage.

5. A main fuel injection system for an internal combustion engine comprising an induction tube, a passage connected to said tube for supplying a rich fuel-air mixture thereto, a fuel-air pump connected to said passage for supplying said mixture to said passage under pressure, and valve means for simultaneously controlling said tube and passage.

6. A main fuel injection system for an internal combustion engine comprising an induction tube, a passage connected to said tube for supplying a rich fuel-air mixture thereto, a fuel-air pump connected to said passage for supplying said mixture to said passage under pressure, a throttle in said tube, a valve in said passage, and means connecting said throttle and valve for simultaneous operation.

7. A main fuel injection system for an internal combustion engine comprising an induction tube, a passage connected to said tube for supplying a rich fuel-air mixture thereto, a fuel-air pump connected to said passage for supplying said mixture to said passage under pressure, and manually operable valve means for simultaneously controlling said tube and passage.

8. A main fuel injection system for an internal combustion engine comprising an induction tube, a passage connected to said tube for supplying a rich fuel-air mixture thereto, a fuel-air pump connected to said passage for supplying said mixture to said passage under pressure, manually operable valve means for simultaneously controlling said tube and passage, and automatically operable mechanism operable in accordance with a variable engine condition for controlling the richness of said mixture.

9. A main fuel injection system for an internal combustion engine comprising an induction tube, a passage connected to said tube for supplying a rich fuel-air mixture thereto, a fuel-air pump connected to said passage for supplying said mixture to said passage under pressure, manually operable valve means for simultaneously controlling said tube and passage, and automatically operable mechanism operable in accordance with load on the engine for controlling the richness of said mixture.

10. A main fuel injection system for an internal combustion engine comprising an induction tube, a passage connected to said tube for supplying a rich fuel-air mixture thereto, a fuel-air pump connected to said passage for supplying said mixture to said passage under pressure, manually operable valve means for simultaneously controlling said tube and passage, and automatically operable mechanism operable in accordance with vacuum downstream of said throttle for controlling the richness of said mixture.

11. A fuel injection system for an internal combustion engine comprising an induction tube, a passage connected to said tube for supplying a rich fuel-air mixture thereto, a fuel-air pump operated by the engine at a rate variable with engine speed for supplying said mixture to said passage under pressure, and valve means for simultaneously controlling said tube and passage.

12. A fuel injection system for an internal combustion engine comprising an induction tube connected to said engine, a throttle in said tube, a passage for supplying a rich fuel-air mixture to said tube, a fuel-air pump operated in accordance with engine speed for controlling the quantity of mixture supplied to said passage, and valve means responsive primarily to load on the engine for controlling the quantity of fuel supplied to said mixture of the mixture.

13. A fuel injection system for an internal combustion engine comprising an induction tube connected to said engine, a manually operable throttle in said tube, a passage for supplying a rich fuel-air mixture to said tube, a mixture valve in said passage, means mechanically connecting said mixture valve to said throttle for conjoint actuation therewith, means responsive primarily to engine speed for controlling the pressure of the mixture in said passage, and means responsive primarily to load on the engine for controlling the richness of the mixture.

14. A fuel injection system for an internal combustion engine comprising an induction tube having a Venturi and a throttle therein, a mixture passage for supplying a rich fuel-air mixture to said tube including a nozzle in the Venturi thereof, a positive displacement fuel-air pump for supplying air to said passage, means connecting said pump to the motor to drive the pump at a speed dependent on engine speed, an air inlet passage connected to said pump havinga second Venturi, fuel supply means having an inlet in said second Venturi, a fuel valve controlling the flow of fuel into said second Venturi, and means responsive to vacuum in said tube downstream from said throttle for controlling said fuel valve.

15. A fuel injection system for an internal combustion engine comprising an induction tube having a Venturi and a throttle therein, a mixture passage for supplying a rich fuel-air mixture to said tube including a nozzle in the Venturi thereof, a mixture valve in said passage, means connecting said mixture valve to said throttle for conjoint movement, a positive displacement fuel-air pump for sup- 15 2,650,081

plying air to said passage, means connecting said pump to the motor to drive the pump at a speed dependent on engine speed, an air inlet passage connected to said pump having a second Venturi, fuel supply means having an inlet in said second Venturi, a fuel valve controlling the flow of fuel into said second Venturi, and means responsive to vacuum in said tube downstream from said throttle for controlling said fuel valve.

References Cited in the file of this patent UNITED STATES PATENTS Modlin Oct. 27, 1925 Holley -t Jan. 28, 1930 Rockwell Aug. 25, 1953 

